This invention relates to automotive suspensions and more particularly to an improved deflection jounce bumper for a suspension strut providing a controlled spring rate to dampen shocks.
Known elastomer or rubber jounce bumpers for controlling MacPherson strut suspension travel at full compression have taken various shapes. As discussed in U.S. Pat. No. 4,256,292 issued Mar. 17, 1981 to Sullivan et al, jounce bumpers are of two main types. The first type is a generally convoluted tube-like member in shape formed of elastomer or rubber material. Convoluted bumpers function by a progressive stacking of the convolutions to provide resistance to jounce forces. Examples of convoluted or ribbed jounce bumpers are found in U.S. Pat. Nos. 4,235,426 and 4,175,770. The main disadvantage of convoluted bumpers is their low initial spring rate requiring large compressive heights.
The second type of jounce bumper is generally a washer-like annular member in shape employing essentially a solid mass of elastomers in straight compression. The U.S. Pat. Nos. 3,954,257 and 4,497,523 are examples of the second type of jounce bumpers which require less compressive height but present excessively high initial spring rates.